North Korea launched a short-range ballistic missile toward the Sea of Japan early Friday, the Japanese government and South Korean military said, the latest in a series of missile tests that have heightened regional tensions.

The missile, launched at around 1:47 a.m., apparently traveled some 650 kilometers at a maximum altitude of 50 km and splashed down outside Japan's exclusive economic zone, some 370 km from its coast, Japanese Defense Minister Yasukazu Hamada told reporters.

Friday's launch was the eighth occasion North Korea has test-fired ballistic missiles since late September and came after North Korean leader Kim Jong Un was reported by the country's official media to have overseen the test-firing Wednesday of two long-range strategic cruise missiles.

Since the start of the year, North Korea has carried out 27 rounds of missile tests, including cruise missiles. But the tests since Sept. 25 have been at an unprecedented pace and include one fired earlier this month over the Japanese archipelago for the first time in five years.

North Korean ballistic missile launches in defiance of U.N. Security Council resolutions have come amid growing speculation that the country could conduct a seventh nuclear test in the near future.

Friday's launch prompted South Korea to impose unilateral sanctions on its northern neighbor for the first time in five years, blacklisting 15 North Korean individuals and 16 organizations involved in the North's nuclear and missile development programs.

In Tokyo, Foreign Minister Yoshimasa Hayashi said at a press conference that Japan supports South Korea's move and will consider what additional sanctions it can impose on the North.

Prime Minister Fumio Kishida (2nd from L) talks to Defense Minister Yasukazu Hamada (R) ahead of a Cabinet meeting at the prime minister's office in Tokyo on Oct. 14, 2022. (Kyodo)

Japan lodged a protest with North Korea through its embassy in Beijing, with Hayashi calling the latest launch "totally unacceptable."

The U.S. State Department condemned the launch and said Washington continues to seek "serious and sustained dialogue" with North Korea but that Pyongyang "refuses to engage."

The South Korean military's Joint Chiefs of Staff said the missile flew about 700 km from an area near Pyongyang at around 1:49 a.m.

The missile possibly flew on an irregular trajectory, the Japanese defense minister said, adding there were no immediate reports of damage to Japanese aircraft or ships.

More than 10 North Korean military aircraft, meanwhile, flew near a no-fly zone set up between the two Koreas from late Thursday to early Friday, prompting South Korea to scramble fighter jets, the JCS said.

The North Korean aircraft reached a point some 5 km north of the no-fly zone on the western side of the Korean Peninsula and a point roughly 7 km north of the zone on the eastern side, the JCS said.

The North also fired about 130 artillery rounds toward the Yellow Sea on the peninsula's west past 1 a.m., followed by around 40 rounds toward the Sea of Japan, which lies east, according to the JCS.

North Korea fired a barrage of artillery shells into coastal waters again late Friday afternoon -- about 90 shells into the Sea of Japan and about 300 into the Yellow Sea, the JCS said. None of the shells, including the earlier rounds, landed in South Korea's territorial waters, it said.

South Korea's Defense Ministry said it has warned North Korea over Friday's provocations through inter-Korea military communication lines.

The ministry said it told the North that the artillery firing in western and eastern maritime buffer zones violate a 2018 military agreement and urged Pyongyang to "abide by it and ensure a similar incident will never happen again."

The bilateral pact, which bans hostile acts by either side in border areas, was signed on Sept. 19, 2018, on the sidelines of the Panmunjom Declaration signed by then South Korean President Moon Jae In and North Korean leader Kim following their summit.

An official of South Korea's presidential office warned also Friday that the future of the military agreement depends on North Korea's attitude.

The official stressed the South Korean government respects this and other military agreements with the North and that Pyongyang should do the same.

"It was North Korea that violated the Sept. 19 military agreement today and therefore, whether it will be maintained depends on North Korea."

The North's official Korean Central News Agency, quoting a spokesman of the General Staff of the Korean People's Army, said North Korea took unspecified "strong military countermeasures" after South Korea conducted artillery fire for about 10 hours near the forward defense area" of the North's military.

The South Korean military is scheduled to hold a field training exercise from Oct. 17 to 28. The drill will be aimed at countering North Korean threats and involve U.S. forces in South Korea, making a further North Korean response likely.

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